What you should know: False-positive mammograms and breast cancer risk

December 14, 2015
| by Letisia Marquez

Women who received a false-positive result on a mammogram may be at a slightly elevated risk for developing breast cancer later, a new study has found. But that doesn’t mean panic is in order for the thousands of women each year who receive such a result.

Researchers stressed that the increased risk is small and that many factors contribute to breast cancer.

The new breast cancer risk study, published in the December issue of Cancer Epidemiology, Biomarkers & Prevention, analyzed more than 2.2 million screening mammograms done on nearly 1.3 million women throughout the United States from 1994 through 2009. Researchers also tracked the women for up to 10 years to find out if a false positive increased their chance of being diagnosed with breast cancer later.

Women who received a false-positive result and were referred to more tests had a 39 percent higher risk of developing breast cancer during the follow-up period than women with a negative result, the study showed. To put that in perspective, one or two additional women out of 100 would develop breast cancer in the next decade.

Women who underwent a biopsy due to a false-positive result had a 76 percent higher risk of developing breast cancer than those with a negative result. Again, that means that an additional one to three women out of 100 would be diagnosed with breast cancer later.

Joanne Mortimer, M.D., vice chair of medical oncology and director of the Women’s Cancers Program at City of Hope, told HealthDay that the study’s findings are no cause for alarm. Rather, she said, women should have a “heightened awareness” about asking their doctor what to do if they have a false-positive mammogram result.

Mortimer added that reading a mammogram is not a simple task.

“It’s not one single abnormality that is looked at that turns out to be a false positive,” she said in the interview. Rather, it’s an accumulation of suspected abnormalities that may prompt a radiologist to call a test suspicious and ask for more testing.

Women with a false-positive result should also follow up with their doctor and ask what screening intervals are best for them, researchers said.